Table 2. Lattice constants and crystallinity of PHAp, 0.25-FPHAp, 0.50-FPHAp, and 0.75-FPHAp. With the rise in fluoride content, the crystallinity of the apatite steadily increased. The incorporation of fluoride also resulted in significant decline of a lattice constant of the apatite, while the c lattice constant did not show any discernable difference.

	Lattice constant (Å)		Crystallinity(%)
	a-axis	c-axis
PHAp	9.42541	6.88685	94.4 ± 1.6
0.25-FPHAp	9.40576	6.88174	96.9 ± 2.2
0.50-FPHAp	9.38676	6.88120	98.7 ± 2.2
0.75-FPHAp	9.38234	6.88467	98.7 ± 1.4